Klinefelter first discovered and described the clinical condition in 1942, so it is also known as Klinefelter’s syndrome, Klinefelter’s syndrome, or Klinefelter’s syndrome for short. 1. Klinefelter’s syndrome is a common sex chromosome abnormality in azoospermia, i.e., chromosome 47, XXY. 2. Clinical manifestations range from a normal male appearance to male gonadotropin deficiency, small, hard testes, scanty hair, distribution of female hair, and lengthening of the arms and lower limbs due to delayed epiphyseal closure. 3. Most patients with Crohn’s syndrome show no sperm in the semen, and a few show very few sperm in the semen. The mechanism of sperm production is not clear. 4. Patients with Crohn’s syndrome are at risk for androgen deficiency, and hormone replacement therapy may be considered as they age. 5. At present, with the advancement of medical technology, some patients with Kirschner’s syndrome who have sperm can have their own offspring through in vitro fertilization (IVF); most of the patients with Kirschner’s syndrome with azoospermia who have the will to have their own offspring can still have their own offspring through the microspermic sperm retrieval technology, and the rate of the microspermic sperm retrieval can reach about 50% at present.